The electrochemical properties of LiNi 0.8 Co 0.2 O 2 coated with ZrO 2 by three different coating processes (ball-milling, sol-gel method, simple grinding) were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). Results showed that the ZrO 2 coating significantly improved the capacity retention of the cathode by suppressing the impedance growth at the interface between electrodes and electrolyte and the best cyclability was obtained in the case of employing the simple grinding for the ZrO 2 coating. On the other hand, the initial capacities of the ZrO 2 -coated LiNi 0.8 Co 0.2 O 2 cathode were slightly decreased.